Around the world 2: Sage & Cooper are somewhere else on WorkCycles bikes
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I wrote in an earlier post about the two ex-Marines riding WorkCycles Secret Service bikes around the world. They previously sent a photo anonymously from their Blackberry (that much I could read in the email) of one of them somewhere in the UK. Well now they’re apparently somewhere else, judging from the different, hilly scenery in this photo. And they’ve traded camera duty thus we see our other protagonist in this story… though I honestly can’t remember which one of the two is Sage. I think it’s the guy in this picture. Detailed descriptions are clearly not their forte.
[UPDATE: In this photo we see Cooper while in the previous photo it’s Sage. Glad that’s cleared up.]
Speaking of riding the Secret Service in terrain hillier than pannekoeken flat Holland and also of non-detailed descriptions, we were tinkering with Shimano roller brakes today. Shimano makes several versions of their nearly maintenance-free roller brake but their literature and website offer almost no information about the differences between them. Countless conversations with the Shimano tech support guys were fruitless. There are three basic versions of roller brakes commonly found on quality bikes:
For about a year or so we’ve been fitting the IM70 to all Bakfiets Cargobikes and the Secret Service, partially because they look cool but mostly because it clearly has a more consistent, snappy feel and is more powerful. This baffled us since the braking unit in the center of each rollerbrake seemed to be exactly the same unit. In theory then there shouldn’t be much difference.
But today our chief mechanic Eric showed me something new: They’d opened up one of each type of rollerbrake to check out the guts and it turns out that the IM70 is actually special. While the IM40 and IM50 share the same flat braking surface (like a drum brake except in steel), the IM70 has a “V” shaped, or rather double conical braking surface. This gives it more braking surface area and probably makes it self-adjusting as well.
The problem though is that the front IM70 doesn’t have it’s own cable stop, thus meaning that it only fits on front forks equipped with a little cable stop tab. Many bikes don’t have these.
Enter the Shimano IM80 roller brake due for introduction shortly. Again the Shimano literature is just worthless marketing garble but at least it’s visible from the photos that the cable stop is built into this one. Let’s just hope that they’re using the better V-shaped brake surface.
Oh, just to back up a little here… “What’s a roller brake” you might ask, or perhaps a little more advanced question: “how is a roller brake different from a drum brake or a disk brake?” I’ll try to explain briefly, without photos. If that doesn’t work I’ll try again later WITH photos.
Drum brake: Two semi-cylindrical “shoes” get pressed against the inside of a cylindrical drum. The drum rotates with the wheel while the shoes are stationary in the frame or fork. The shoes are pressed outward at one end by means of a cam. More sophisticated drum brakes have been fitted to motorcycles and cars but, to my knowledge, never to bicycles.
Disk brake: A disk rotates with the wheel and the sides of the disk get squeezed by flat pads. The pads can be either cable actuated through a helix or hydraulically actuated.
Roller brake: The IM40 and IM50 are basically just drum brakes with a six lobed actuation cam that presses the shoes outward radially over their whole length instead of just at one point. The roller brake shoes are also steel, running in a bath of special graphite grease. Does your rollerbrake make noise? Squirt fresh grease in.
The IM70 roller brake has the same actuation as the IM40 and IM50 but uses a special type of drum described above.
I’m sure that’s all just totally clear for you know.
August 19th, 2009 at 20:11
im80… excellent, so should in theory be retro-fittable to all roller’d bikes?
August 19th, 2009 at 20:29
Todd, Yes, in theory the IM80 should fit any frame and any fork with a reaction arm holder. In reality experience tells us that some frames/forks don’t have adequate clearance but a couple washers can usually remedy that.
August 20th, 2009 at 00:59
Henry,
Just curious. Why was the IM70 not spec’d on the FR8? I’m stopping just fine, and do so even on steep (but short) downhills with load. But maybe one day I’ll long for something with more stopping power and the IM80 might be a calling.
August 20th, 2009 at 06:38
David,
Ah, I was just waiting for somebody to ask that obvious and slightly embarrassing question. We originally planned to fit the IM70 on at least some versions of the Fr8 (little “r” BTW) but then the first batch of forks came without the little tab for the cable stop so it wasn’t possible. Adding the cable stop tab is planned though when the IM80 becomes available we’ll check that one out to see whether it’s better than the IM70.
August 20th, 2009 at 22:23
Henry,
Thanks for the nice overview on roller brakes. I always wondered what made them different than a drum brake. Being that it is very flat in the Netherlands you might not be the right person to ask this question. Do roller brakes overheat more than drum brakes? I am sure that the initial stopping power is greater, I am just concerned that they may not dicipate the heat as well as a traditional drum brake.
August 20th, 2009 at 22:50
Mark, That’s a good question about how different kinds of brakes will be influenced by heat. It might be flat in the Netherlands but I’ve also lived in New York, Vermont, Colorado and California and built high-performance motorcycles and racing cars… so maybe I have a little insight here.
It’s quite possible that the IM40 roller brake with it’s small housing and no air cooling beyond the compact steel shell is quite poor at dissipating accumulated heat. The IM70 though has about as much heat absorbing and more dissipating capacity than any bicycle drum brake I know of with the possible exception of the old Arai tandem drum… but that’s another story.
The roller brake also has two other advantages with respect to heat:
1. The roller brake is independent of the hub so even heating it red hot will have no significant effect on the hub itself. Drums can warp and ovalize under extreme conditions.
2. If you do manage to kill a roller brake you can simply remove it, toss it in the scrap metal bin and install a new one. If you kill a drum brake you’ll probably be throwing out the entire hub (possibly including internal gear hub!) and then lacing a new wheel up.
Just to add: In case I sound like a big Shimano fan, I’m absolutely not. We often find them to be an arrogant and unhelpful supplier who abuses their position of power in the bike industry. However they sometimes get products right and basically leave them that way for years, and the roller brake is the best example of this.
August 21st, 2009 at 14:47
Thanks for the update. I can’t wait to hear future updates from the jar-heads’ world tour. It sounds like a blast and I wish I be with them. Send them my most sincere semper fi.
August 23rd, 2009 at 12:22
Henry,
Thanks for the explanation of the roller brakes. Also many thanks for helping me get and upgrade to the IM70 on my bike. The IM40 is marginally suitable on a bike that is going to gross around 165kg(310#) loaded. I also agree that Shimano is a PITA to deal with, from several points of view.
Interesting update on your two itinerant travelers, too bad they didn’t set up a blog that they could keep updated from their blackberry. I will be interesting in seeing how they progress.
Aaron
September 23rd, 2009 at 15:31
Henry, first of all thank you for maintaining this blog. Its entertaining but also really one of the few places where I can find the info that I am looking for. If the new IM80 set will fit on a bakfiets that was sold with IM40s (probably just before you switched to IM70) then I will put in an order ASAP! I called the guys in the workshop but you only have a prototype at the moment. In can confirm that the IM40 on a bakfiets under load is not up to the task (its shit, actually) and I can’t wait to upgrade. A friend has a flat bar road bike with the IM70 and those brakes felt pretty good. I would have gone for the IM70 earlier but my front fork is not suitable. At this point I may as well hold out a bit longer and go IM80, if they can be retrofitted.
Happy riding,
Cheers,
Hielke
September 23rd, 2009 at 16:11
Hi Hielke, Thanks very much for the compliment! As you probably heard we just received the IM80 prototypes for testing so we’re obviously not yet 100% sure they’re the answer to our questions. But certainly from what we know so far they should only be an improvement over the IM70’s which are already a huge improvement over the IM40’s. It’s also worth noting that we don’t yet have prices for the IM80. They might be expensive considering that the price difference between the IM70 and IM40 is commensurate with the braking improvement.
Barring any strange interferences between the brake and the Cargobike’s frame or fork the IM80 should fit without problem, and even then we’d figure out how to make them fit.
September 10th, 2010 at 21:39
Hello, I have a well-loved v1.0 bakfiets. Was wondering what the verdict was on the UM80’s. Also, is it possible to at least fit UM70’s on the rear.
Thanks.
September 11th, 2010 at 17:18
Allan,
Though the Bakfiets Cargobike 2.0 is stiffer and has a few other advantages we still prefer version 1.0 in a number of ways. IM80 rollerbrakes will fit your bike without problem and are absolutely a worthwhile upgrade. We’ve had them on a number of test bikes for a year without issues. The only problem is that you might have trouble finding a set. Thus far they’re only been sporadically available in the Netherlands and Germany.
Also if your Cargobike is fairly old you’ll want to upgrade the cable housings to the linear strand, compressionless type (as fitted for the last few years… but NOT the similar looking derailleur cable housing which will explode under braking forces!) and lubricate them very thoroughly.
Once complete you’ll be amazed at the improvement in braking power.
September 12th, 2010 at 01:58
Allan, I was going through the same issue exactly a year ago when my 1.0 bakfiets had IM40s. I did the upgrade and I concur with Henry when he says they fit without problem and they are absolutely a worthwhile upgrade. All I can say is do it. It is not that expensive. I had my brakes installed when I brought my bike in for a complete keep-it-beautiful-and-ship-shape service.
Interesting point about the compressionless cable housing. This is exactly what my mechanic told me but which I never understood. I thought what probably would really help is reduce the ‘slack’ in the cable. I thought it would be because the actual brake cable would stretch under load, but he said it had to do with the compression of the cable. He was a metal engineer by trade and I’m an economist so we more or less talked passed each other. Since the IM80 was already a dramatic improvement over the IM40 with the old cables I just left it at that. Whenever I get to Amsterdam again I will come and check it out so I can fully understand.
A new set of IM80 roller brakes isn’t that hard to find. Google is your friend. I bought mine a year ago in Berlin.
Keep riding and stay upright,
Cheers,
Hielke
September 12th, 2010 at 07:50
Thanks Henry and Heike for the update. I’ll definitely put them on my wish list.
September 12th, 2010 at 07:51
Sorry. I meant, Hielke. My eyes must have crossed as I was typing.
May 17th, 2013 at 04:02
Would an American bicycle mechanic easily confuse the compressionless brake housing with derailleur housing? I had my bakfiets (bought in 2011, brakes say IM70) tuned today at our local shop (which works mostly on road bikes, not cargo/utility bikes). The mechanics replaced the brake cables and housing and were surprised/concerned, telling me that derailleur cable was used for the brakes. Are they confused about something uncommon in America? It’s hard for me to imagine the dealer we bought the bakfiets from would install derailleur cables for the brakes… I have the old brake cables, as well as the old gear cable; I’m curious how you tell the difference, since I just see linear strands in both… Still need to ride the bike fast/ fully loaded to see if braking feels much different… Thanks.
May 17th, 2013 at 08:53
Kimberly,
Compressionless brake cable housing looks like the compressionless shifter cable housing but has an extra layer over the linear strands to prevent it from exploding under the far greater forces of braking. There are different types but usually it’s a braided layer of Kevlar or other strong fabric between the linear steel strands and the plastic out casing.
If the housing is thin in diameter (4mm) then it’s definitely shift-only version. Being fat though doesn’t guarantee that it’s the reinforced brake housing either. Some linear strand shift housing is just as fat as brake cable housing.
Another clue is whether the housing has some visible pattern or texture. The compressionless brake cable housing is expensive so manufacturers generally want to show off the fact that they’re using it. Ours is a sort of dark smoke color and the reinforcement layer can be seen and felt.
If it isn’t already clear NEVER EVER USE LINEAR SHIFT CABLE HOUSING FOR YOUR BRAKES. IT WILL EXPODE, LEAVING YOU WITHOUT BRAKES!
May 18th, 2013 at 22:40
OK… I can’t really tell, but I think it was the compressionless brake housing on the bike. Don’t worry… I won’t ever put it back on, since I can’t tell for sure. There’s just regular brake cable and housing on there now, which seems to be working fine. Thanks for the reply.
May 20th, 2013 at 11:10
Kimberly, Just to be clear it is important that your bakfiets has compressionless cable housing… but it has to be the correct, brake-reinforced type.
May 20th, 2013 at 16:48
Is the compressionless housing just stronger/ needed for the heaviness of the bakfiets or something necessary with the roller brake?… I’m pretty sure that what’s now on there isn’t compressionless. Maybe I’ll bring it back to the shop to figure out for sure what they put on…